Aetiology and pathophysiology of asthma

Question 1

What is asthma?

Answer 1

The hypersensitivity of hyperinflation of airways that become narrow and clogged with mucus in response to certain tirggers

Question 2

What are the common triggers of asthma?

Answer 2

infection, nighttime or early morning, exercise, animals, cold/damp, dust, strong emotions, occupation exposure, pollutants

Question 3

What happens to the airway muscle in asthma?

Answer 3

The smooth muscle contracts to make the airways tighter and narrower, the airways become “twitch” and contracts more easily and stronger

Question 4

What happens to the airways as a result of inflammation?

Answer 4

The inside walls of the airways become swollen and inflames, leaving less space inside them

Question 5

What happens to mucus in asthma?

Answer 5

It is excessive and can block the inside of the airways

Question 6

What happens to the lung tissue in patients with asthma?

Answer 6

ongoing inflammation can lead to the development of scar tissue and tissue remodelling. This results in thicked airway walls and increased smooth muscle

Question 7

What is atopy?

Answer 7

Atopy is a problem with the immune system which makes individuals more likely to develop allergic diseases and sensitive to triggers

Question 8

When does atopic asthma begin?

Answer 8

It usually begins in childhood, when it is triggered by environmental antigens, such as dusts, pollen, animal dander and foods.

Question 9

What happens in atopy?

Answer 9

When an allergy enters the body the immune system overacts and created antibodies called immunoglobulin which release chemicals that cause allergy symptoms in your body.

Question 10

What causes atopy?

Answer 10

Genetic causes, 80% of people with atopy have other family members with allergic diseases.

Question 11

What are the conditions related to atopy?

Answer 11

Asthma, eczema, allergic rhinitis, allergies to shellfish

Question 12

What is bronchial hyperresponsiveness?

Answer 12

An increase in sensitivity to a wide variety of airway-narrowing stimuli, which can be both chemical and physical

Question 13

What does the hyperactivity of the bronchial smooth muscle?

Answer 13

bronchoconstriction, increasing airflow resistance and decreased airflow

Question 14

What is fixed bronchial hyperresponsiveness more influenced by?

Answer 14

airway inflammation but more by structural changes of the airway which persist after the inflammation has been supressed.

Question 15

What is episodic bronchial hyperresponsiveness influenced by?

Answer 15

the acute effects of airway inflammation

Question 16

What type of hypersensitivity response is initiated in asthma?

Answer 16

Typ1 1

Question 17

What happens in the type 1 hypersensitivity response?

Answer 17

Th2 cells activate downstream B cells to produce immunoglobulin E (Ig-E), which mediates the release of antibodies against the soluble antigen

Question 18

What is the result of the Ig-E release?

Answer 18

Mast cell degranulation and release of histamine and other inflammatory mediators, including proteinoids, platelet activating factors and leukotrienes, create a cycle of chronic inflammation.

Question 19

What does chronic inflammation because of type 1 hyperresponsiveness lead to?

Answer 19

bronchoconstriction and epithelial damage, leading to remodelling of the airway and bronchospasm.

Question 20

What is bronchospasm?

Answer 20

Bronchospasm is when the muscles that line the bronchi start to contract and spasm, which causes airway narrowing

Question 21

What is the effect of bronchospasm on gas exchange?

Answer 21

This reduces the amount of oxygen that enters the blood and the amount of carbon dioxide that leaves the blood.

Question 22

What noise is made as a result of bronchospasm and why?

Answer 22

Wheezing, because of bronchoconstriction the airflow through a narrowed airway becomes turbulent, causing vibration of the airway walls; this vibration produces the sound of wheezing.